As much as I hate to dissect this, perhaps some explanation is required. There is a number of meanings here.

One: “On the glistening (white) dew atop the ordinary grass.”

This reads arifureta to mean “ordinary/common place” (有りふれた).

Two: “In the glistening (white) dew atop the grass, an ant swayed.”

This reads arifureta as a combination of the noun ari (蟻) “ant” and the past of fureru (振れる) “to shake.”

白露 shiratsuyu means literally “white dew,” but since “white” has the connotation of being clear and transparent, “glistening dew” is often preferred. 白露 also happens to be an Autumnal seasonal word (kigo 季語, especially for sometime around Sept. 8th) .

It may also be fruitful to note that arifureta can mean “hackneyed,” kusa can be used to refer to writing, and tsuyu is often used in a bit of poetic confusion to mean “tears.” So perhaps we can read this as crying over a piece of hackneyed writing, most likely one’s own.

But this all probably makes very little sense unless you are somewhat familiar with the Akutagawa section of the Isemonogatari 伊勢物語 (The Takes of Ise), and specifically its 6th section.

It relates the tale of “a man” who stole away with a woman one night, and came to the banks of the Akutagawa. There the woman (inexplicably) noticed some dew on the grass, and asked him what it was (くさのうへにをきたりけるつゆを、かれはなにぞとなむおとこにとひける). The night grows dark and a storm moves in, so the man shuts the woman up in a dilapidated warehouse, and sits guard outside the door with his bow and arrows. What he didn’t know was that there were demons in the warehouse, and one gobbles up the woman in a single bite (her scream goes unnoticed on the account of the thunder). The next morning, realizing what had happened the man writes a poem:

しらたまかなにぞと人のとひし時つゆとこたへてきえなましものを

“When she asked me whether it was pearls (shiratama 白玉, literally “white spheres,” but I’m translating it this way for its implications)